Silver halide color photographic materials commonly employ three different photographic silver halide emulsion layers that are formed on a base and which are spectrally sensitized to have sensitivity to blue, green and red regions of light. For example, in silver halide photographic materials for use as color negatives, a base is coated, in order from the exposure side, with a blue-sensitive silver halide emulsion layer, a green-sensitive silver halide emulsion layer and a red-sensitive silver halide emulsion layer. A bleachable yellow filter layer is disposed between blue- and green-sensitive emulsion layers in order to absorb blue light that has passed through the blue-sensitive emulsion layer. Each of the emulsion layers is provided with other intermediate layers that serve to accomplish various functions, and a protective layer is provided as the outermost coat. In silver halide photographic materials for use as color prints, the base is coated, in order from the exposure side, with red-, green-, and blue-sensitive silver halide emulion layers and, as in the case of silver halide photographic materials for use as color negatives, various intermediate layers such as an ultra-violet absorbing layer, and the protective coat are provided. The aforementioned silver halide emulsion layers may be arranged in orders that are different from those specified above. If desired, each of the silver halide emulsion layers may be a light-sensitive silver halide emulsion layer that is composed of two layers having sensitivity to light in substantially the same wavelength range but which have different degrees of sensitivity. With the silver halide color photographic materials described above, a color developing agent, typically an aromatic primary amino color developing agent, is used to develop exposed silver halide grains and the resulting oxidation product of the color developing agent reacts with a dye forming coupler so as to form a dye image. In this process, a cyan dye image is customarily formed with the aid of a phenolic or naphtholic cyan coupler, a magenta dye image is formed with the aid of a 5-pyrazolone, pyrazolinobenzimidazole, pyrazolotriazole, indazolone or cyanoacetyl based magenta coupler, and a yellow dye image is formed with the aid of an acylacetamide based yellow coupler. These dye forming couplers are incorporated in either the appropriate light-sensitive silver halide emulsion layer or in the developing solution. The present invention relates to a silver halide color photographic material of the type wherein the aforementioned couplers are incorporated in the appropriate silver halide emulsion layers in a non-diffusible form.
The modern photographic industry strongly needs silver halide color photographic materials that can be processed rapidly and in a consistent manner using a reduced amount of silver and having good keeping quality. Among all other thins, rapidly processable silver halide color photographic materials are the goal of all photographic engineers. It is common practice at modern laboratories to process silver halide color photographic materials by running treatment with an automatic developer. In order to meet the consumer's demand for rapid access to the pictures they have taken, the laboratories are required to complete the necessary processing within the day of receipt and to return the film to the customer together with the processed print. In an urgent case, these procedures must be completed within several hours from the time of receipt. A situation therefore exists for providing very rapidly processable silver halide color photographic materials.
Another problem with the running processing of silver halide color photographic materials is that prints with consistent photographic performance cannot be obtained since their photographic characteristics are highly sensitive to any variations in the compositions of the processing solutions and in the processing conditions that will occur between different laboratories or even at the same laboratory. Such variations in the compositions of the processing solutions and in the processing conditions are believed to result principally from the dissolution of photographically active substances out of the photographic material being processed by the running method and from subsequent accumulation of the dissolved substances within the processing solutions. In order to accommodate the variations in the processing conditions, it is required to closely control the time of development, the temperature and pH of the developing solution, as well as the concentrations of halides, especially bromide ions. The fact is, however, that the concentration of bromide ions in the developing solution is difficult to determine quantitatively and, hence, to control precisely as compared with the time of development and the temperature and pH of the developing solution. It is therefore necessary to develop a silver halide color photographic material whose photographic performance is less dependent on the bromide concentration and which can be processed in a highly consistent manner. This requirement is of course important for processing by the conventional scheme but is by far more important for rapid processing purposes. Needless to say, the silver halide color photographic material that can be processed in a consistent manner should also be processed using a reduced amount of silver and must be offered at an economically feasible price. Another inevitable requirement is that such silver halide color photographic material should withstand extended storage without undergoing any impairment of its photographic characteristics.
Several prior art methods have been proposed for producing rapidly processable silver halide color photographic materials; they include (1) preparing very fine silver halide grains as described in Unexamined Published Japanese Patent Application No. 77223/1976; (2) preparing a silver halide composition with a reduced content of silver bromide as shown in Unexamined Published Japanese Patent Application No. 184142/1983 and Japanese Patent Publication No. 18939/1981; and (3) incorporating a 1-aryl-3-pyrazolidone with a specified structure in the silver halide color photographic material as disclosed in Unexamined Published Japanese Patent Application, No. 64339/1981 or incorporating 1-arylpyrazolidones in the silver halide color photographic material as shown in Unexamined Published Japanese Patent Application Nos. 144547/1982, 50534/1983, 50535/1983 and 50536/1983. Also known is the use of a color development accelerator when an exposed silver halide color photographic material is developed with an aromatic primary amino color developing agent. Compounds suitable for use as such color development accelerator are shown in U.S. Pat. Nos. 2,950,970, 2,515,147, 2,496,903, 4,038,075 and 4,119,462; British Pat. Nos. 1,430,998 and 1,455,413; Unexamined Published Japanese Patent Application Nos. 15831/1978; 62450/1980, 62451/1980, 62452/1980, 62453/1980, 12422/1976 and 62453/1980; as well as Japanese Patent Publication Nos. 12422/1976 and 49728/1980.
The methods (3) and (4) are capable of shortening the processing time but they are unable to ensure a high degree of consistency in rapid processing and the processed photographic material will fog within 24 hours. When a silver halide emulsion with a reduced silver bromide content is used in accordance with the method (2), rapid processing is possible since a reduced amount of bromide ions will dissolve into the processing solution from the silver halide color photographic material incorporating said low-silver bromide emulsion. The problem, however, is that only a low degree of consistency is achieved in processing the silver halide color photographic material with the processing solution having a low concentration of bromide ions. The "consistency in processing" is expressed by sensitometric changes resulting from variations in the composition of the processing solution, pH, temperature and the concentration of bromide ions, as well as from the entrance of undesirable compounds into the processing solution.
The method (1) depending on the use of tiny silver halide grains is unable to attain a high degree of consistency in processing and, furthermore, the sensitivity of silver halide grains is deteriorated as they become smaller in size.
As disclosed in Unexamined Published Japanese Patent Patent Application Nos. 121036/1984 and 120250/1984, the degree of consistency in processing is conventionally improved by means of improving the composition of a specific processing solution, but to the best knowledge of the present inventors, no attempt has been made to achieve substantial improvement in the consistency of processing by means of employing a silver halide color photographic material with an improved composition.
As mentioned earlier in this specification, a blue-sensitive silver halide emulsion layer in the silver halide photographic material for use as color paper is disposed closest to the base and has the greatest need for improvement in developability. With a view of enabling rapid processing by means of improving silver halide color photographic materials, the present inventors previously made an attempt at incorporating a highly reactive yellow coupler in the blue-sensitive silver halide emulsion layer and the resulting product did have the capability of rapid processing. However, extensive fogging occurred in this material during rapid processing and the processed material did not have the desired long keeping properties.
On the basis of these findings, the present inventors filed Japanese Patent Application No. 202058/1984 on an improved silver halide color photographic material having blue-, green- and red-sensitive silver halide emulsion layers on a base. The proposed photographic material was characterized in that the blue-sensitive silver halide emulsion layer contained at least one highly reactive yellow coupler having a relative coupling rate of 0.3 or more and that the green-sensitive silver halide emulsion layer contained at least one compound represented by Formula (A): ##STR2## where R.sub.5 is a halogen atom or a monovalent organic group capable of leaving upon coupling reaction with the oxidized product of a developing agent; R.sub.6 and R.sub.7 which may be the same or different each represents a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an acylamino group, an alkylamino group, an anilino group, an alkoxycarbonyl group or an alkylthio group, provided that R.sub.6 and R.sub.7 are not a hydrogen atom at the same time.
The proposed silver halide color photographic material can be processed rapidly in a consistent manner and without experiencing extensive fogging, and the so processed material has long keeping quality.
The present inventors continued their studies on the above proposed technique and found the following. The magenta dye image forming couplers that are extensively used on a commercial scale and which have constituted the subject of active research work are practically limited to 5-pyrazolones. The dyes formed from the 5-pyrazolone based couplers are highly resistant to heat and light but have an unwanted yellow absorption band at a wavelength in the neighborhood of 430 nm, causing undesirable color contamination. Nuclei of magenta dye image forming couplers that are known to be capable of reducing the unwanted yellow component in the absorption spectrum include the pyrazolobenzimidazole nucleus shown in British Pat. No. 1,047,612, the indazolone nucleus shown in U.S. Pat. No. 3,770,447, and the pyrazolotriazole nucleus disclosed in U.S. Pat. No. 3,725,067. The dye formed from the 1H-pyrazolo[3,2-C]-s-triazole type coupler represented by Formula (A) in accordance with Japanese Patent Application No. 202058/1984 has a smaller degree of the undesirable absorption in the neighborhood of 430 nm within a solvent such as ethyl acetate or dibutyl phthalate, and is further characterized by a minimal absorption tall in the long-wavelength side of the absorption curve. However, the resulting azomethine dye is very low in lightfastness and causes highly deleterious effects on the performance of color photographic materials, especially those for use as color prints.